Typical electromagnetic relays include such an electromagnetic driver, an example of which is disclosed in Japanese Patent Application Publication No. 2015-170562, which is referred to as a published patent document. A conventional electromagnetic relay disclosed in the published patent document includes a coil, a movable core, a stationary core, a return spring, a stationary contact member, a movable contact member, and a contact pressure spring. The coil is configured to generate a magnetic field when energized. The movable core is disposed to be away from the stationary core, and is configured to be reciprocable with respect to the stationary core. The dimension, i.e. the size or length, of the gap, i.e. interval, between the movable core and the stationary core in the reciprocation direction will be referred to as a gap dimension. When the movable core is disposed at a predetermined original position, the gap dimension has a maximum value. In other words, the movable core is configured to start to move toward the stationary core from the original position at which the gap dimension has the maximum value.
The coil is configured to pull the movable core to the stationary core when energized. The return spring is configured to urge the movable core in a direction away from the stationary core. That is, the pulling force of the coil and the urging force of the return spring enable the movable core to be reciprocated with respect to the stationary core.
The stationary contact member is connected to an external electrical circuit, and the movable contact member is configured to follow the movement of the movable core to be in contact with or in separation from the stationary contact member. The contact pressure spring is configured to urge the movable contact member toward the stationary contact member.